Questions — and the answers, including the unflattering ones

Free and open source. No account, no subscription, no paid tier and no telemetry collected about you.

Yes. Change it for yourself and nothing at all is asked of you — the licence conditions passing a copy on, not what runs on your own rig. Publish something built on it and the one condition is that your source is open too, under the same AGPL v3, with this project credited. Keeping your own source closed, or selling a product with this code inside it, needs written permission first — rgoshbbb@gmail.com. The licensing page says it in full.

Yes. The desktop side is a native Linux binary. The in-game panel additionally needs a small bridge running inside the game's Proton prefix, because only a Windows process in there can give the shared memory the name the game is allowed to open. The application ships the bridge and can fetch a matching one for you — the download page has the two commands.

The desktop side is a terminal application at about 0.1 % of one core with no GPU cost at all. The in-game panel draws and nothing else — every calculation happens outside the game, because Lua runs on the render thread where a millisecond is a sixth of the frame budget at 165 Hz. The rules that keep it cheap are written down.

Assetto Corsa, in full. Assetto Corsa Competizione since v0.4.0 for everything it measures — its telemetry is read off a real recorded session, and the engineer judges a GT3 by a GT3's numbers — with two honest gaps: no in-game panel, because Custom Shaders Patch is an Assetto Corsa mod, and no camber advice, because ACC publishes no inner or outer tyre temperature. A simulator is a folder rather than conditionals through the middle of the engineer, and what each game reports is a table rather than a promise.

Only for the in-game overlay. Everything else — the dashboard, the analysis, the engineer, the strategy work — runs without it.

Yes. Laps are saved as JSON with full metadata and can be loaded back as a ghost on another day, and the corner analysis compares against whichever lap you choose.

Yes, and not as a summary. Open LAN, press one key each, and pick each other out of a list — the copies find each other on the network, so nobody reads an IP address out loud. What travels is the whole reading, so their machine finds the laps, builds the traces, draws the map's line and writes its own advice in their units and their language: the dashboard, the analysis and the engineer are all of your driving. It works between the terminal and the window in either direction. It is off unless you turn it on, because it is telemetry about a person, and there is no server in the middle — on one network that is all there is to it. Across the internet, see the next answer.

Yes, and it needs no server of ours. Two houses behind two routers cannot dial each other, so put both machines on one private network with a mesh VPN — Tailscale or ZeroTier, free for a handful of machines — and then use the addresses it gives you in the same two boxes that already work on a LAN. Nothing in the program changes: the watcher presses W and leaves the listening address alone, the driver presses S and types the watcher's mesh address. A mesh VPN carries no multicast, so the two will not find each other in the list — typing the address is the case that box exists for. It costs about half a megabit a second one way, which is less than a video call. The exact settings are here, along with a probe that tests the link before anybody is waiting on it.

It writes one folder — its own overlay app — into the game's Lua app directory, and nothing else. It reads the game's shared memory, which is the interface the game publishes for exactly this: no injected code, no hooks, no modified game files.